My dad taught me that it was ok to punch another kid (I was a boy in the 80s) if they were being a jerk. He even taught my brother, who was a big, slow-running kid, to wait until they were changing in the locker room so they couldn’t run away. This was when we were 8-13 or so- after that, my dad told us it was too dangerous to fight.
I think this was beneficial for both of us- we both learned to stand up for ourselves- and we only got in fights a handful of times as kids. I got in trouble once, but my dad came and backed me up, and it was over.
But times may be different now, and my wife and I are thinking about kids soon. What are your experiences, as parents and kids?